Leon Chua, a professor at the University of California at Berkeley, said 37 years ago that there should be a fourth fundamental circuit next to resistors, capacitors and inductors. Resistors resist the flow of electricity, capacitors store electricity, inductors resist changes to the flow of electrical current and the fourth theoretical circuit, which Chua called a memristor, would register how much current had passed.
HP scientists finally managed to create world's first memristors. These circuits could be used to create very dense, energy-efficient memory chips:
Williams and other scientists at Hewlett-Packard are publishing a paper in Nature on Wednesday demonstrating that that these things actually exist. HP has a few discrete memristors as well as a silicon chip embedded with memristors. It's a first, according to HP.
If memristors can be commercialized, it could lead to very dense, energy-efficient memory chips. Scientists have made devices that function like memristors, but it took a good number of transistors and several capacitors, Williams said. Memristor chips would function like flash memory and retain data even after a computer is turned off, but require less silicon, consume less energy, and require fewer transistors.
A memristor effectively stores information because the level of its electrical resistance changes when current is applied. A typical resistor provides a stable level of resistance. By contrast, a memristor can have a high level of resistance, which can be interpreted as a computer as a "1" in data terms, and a low level can be interpreted as a "0." Thus, data can be recorded and rewritten by controlling current. In a sense, a memristor is a variable resistor that, through its resistance, reflects its own history, Williams said.